After it was welded, they clamped on a midget-size radar transmitter to beam a signal so that the hole in the outer wall could be easily found from outside. The weldor went out through the airlock in the "Bug," which was the only possible spacesuit for the vacuum of interplanetary space. The Bug was a steel carriage with a dome and a flat bottom. You could think of it, if you wanted to, as the shell of a big turtle. It traveled on magnetic rollers that prevented it from being accidentally dislodged from the ship.

Those who didn't were babies and nursing mothers. Tal and Ben were lucky enough to get far forward in the long line. "Keep close to the ship," they were cautioned as they were handed their respirators. They promised, and walked over to the door to the airlock, where a guard had been stationed to see that everyone had a respirator. "Don't put your respirators on," the guard was continually saying. "You will be breathing normal air in the airlock. Don't put them on. " They waited in the airlock until ten people had been admitted-all that the little chamber would comfortably hold.

No particular brains. " "Now wait," the Exec said. " "I'm not," Tal answered. "That was just build-up. I don't expect you to take my word for it. But my father had a reputation for knowing what he was talking about. He knew there was a wall around Venus. He tried to tell me about it. " The Exec said thoughtfully: "Tal, you may be right or wrong, but it's a possibility, and something ought to be done about it. " "Weld on lightning-rods," Ben suggested. "Or maybe you'd have to call them lightning-rods-inreverse.